I'm looking at my modded picture from a different mental vantage-point and the glint in the red circle
may just be a reflection...
...but that gap band is visible in other pictures you put up, 'chute...and the disparity between the axis of the block and the axis of the polished crest of the face really doesn't look right.
I can't touch John French in knowledge or experience of these matters...absolutely not...I want to make it clear that any and all of my comments should be taken as opinion, but I have tweakered enough in the last two years to (I feel) understand the mechanics of the tape-to-head relationship, and my experience is almost exclusively with that very Teac head...I've got 8 of them at my place between my 48 and 58 and their parts decks in various states of wear, though nearly all are relatively low hours, and none have been relapped that I can tell, and
I think all have a more pronounced peak to the crest of the head face...dunno...
If I get a chance I'll measure the distance from the bottom of an edge-relief slot to the peak of the head on one of the heads on my 48 (which are the least worn of any of my heads) and put it up here. If you get into a tussle with JRF
which would just be an absolute shocker and you have access to a dial caliper you can do the same and that may shut the door on the debate as to whether or not the head is new and defective, or used and poorly relapped.
Hope this gets resolved for you soon.
Couple shots of my 48 heads for reference...not sure if they are helpful or not.